I've heard this off and on for some time. Never really trusted that theory though, just seems to me a PH swing be it because of adding something that changes it like wood or peat moss, would be the same as a PH changed because of CO2. Subbing this so I see some other opinions on this.

Yeah it sounded suspect to me too... but i then I read it on a post by Tom Barre, who usually seems to know all